The present invention relates to measuring fuel heat content of fuel, and more particularly, to measuring fuel heat content while a combustion turbine system is on-line and/or running.
The measurement of the fuel heat content of fuel is an important factor in controlling the combustion of the fuel. However, in a deregulated power generation market, it is desirable that power production be as inexpensive as possible. In an effort to produce inexpensive power, typically, the most inexpensive fuel is used. Unfortunately, these inexpensive fuels have fuel heat content that varies dramatically from the rated heating value of the fuel. Therefore, controlling the combustion of these inexpensive fuels has become increasingly complex.
Typically, the fuel heat content is measured by performing various tests on the fuel in a laboratory or other controlled setting. These tests can include calorimetric, stoichiometric, constituent analysis and catalytic combustion. In general, the laboratory tests provide a fuel heat content measurement for the fuel under controlled conditions and do not provide an on-line determination of the fuel heat content while the combustion turbine system is on-line and running. An on-line measurement of the fuel heat content would allow the control parameters associated with the combustion turbine system to be adjusted such that the maximum operational efficiency of the combustion turbine system is achieved. In addition, an on-line measurement of the fuel heat content would allow control parameters associated with the combustion turbine system to be adjusted to avoid damage or increased wear caused by the changes of temperature and pressure in the combustion turbine system that are associated with a change in the fuel heat content. Therefore, a need exists for a method of measuring the fuel heat content while the combustion turbine system is on-line and running.
Presently, fuel heat content monitors are available that can measure the fuel heat content while the system is on-line. The fuel heat content monitor is a separate device that requires installation and additional data monitoring. However, these fuel heat content monitors are expensive. As such, in an effort to produce energy at the lowest price, the added cost of these fuel heat monitors and the cost associated with monitoring the heat fuel content data makes the use of the heat fuel content monitors impractical. Therefore, a need also exists for a method of measuring fuel heat content that does not require the purchasing of expensive equipment. Also, a need exists for a method of measuring fuel heat content that uses conventionally monitored data and does not entail the costs associated with additional data monitoring.
In combustion turbine systems, many control and operational parameters are measured, such as, but not limited to, temperature, pressure and fuel flow. Typically, changes in the fuel heat content result in changes in the measured parameters. During monitoring of these parameters, it is important that any change in these measured parameters that is attributable to changes in the fuel heat content be readily determined. Such a determination can prevent unrequired maintenance on the combustion turbine system. Since unrequired maintenance can increase the cost of the power generation, it is desirable that only required maintenance be performed on the combustion turbine system in order to keep the power generation costs to a minimum. Therefore, a need exists for an on-line measurement of the fuel heat content that determines whether changes in the control and operational parameters are attributable to changes in the fuel heat content.